Lawn-mower.



' A. B. CASE.

LAWN MOWER.

APPLICATION FILED JAN. 28, 1909.

Patented June 7, 1910.

WITNESSES:

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ADELIBERT B. CASE, OF SPRINGFIELD, MASSACHUSETTS.

LAWN-MOWER.

Application filed January 28, 1909.

To all whom it may concern:

Be it known that I, ADELBERT B. CASE, a citizen of the United States ofAmerica, residing at Springfield, in the county of Hampden and State ofMassachusetts, haveinvented new and useful Improvements in Lawn-Mowers,of which the following is a specification.

This invention relates to lawn mowers, and the object thereof is toprovide a cuttershaft for such machines embodying automaticallyadjusting bearings and also means to so counterbalance the shaft in itsbearings as to confine it against longitudinal movement regardless ofthe movement of any part of the self-adjusting bearings of said shaft.

On October 29, 1907, a patent numbered 869,771 was issued to me for animprovement in lawn mower construction which embodied a cutter-shafthaving hearings in the side-plates of the frame, which bearingscomprised a tapered bearing surface and a supporting element therefor,and means to maintain a yielding contact between said bearing surfaceand said supporting element. This effect was accomplished by putting astiff spring member between an abutment on the shaft and a cone slidableon the latter, yieldingly held in bearing contact with a supportingsurface, for instance,a set of balls,-by the expansive action of saidspring. An alternative construction was shown and described in which thecone was fixed. to the shaft, and the spring was placed behind theball-cup, the abutment in that case being the frame of the machine. In

either case, the expansive action of the spring would result inimparting endwise movement to the cutter-shaft during any self-adjustingmovement of the bearing elements, due either to the change of relationof one side of the frame relative to the other or to any wear in thecontacting bearing surfaces. Theme of the many lawn mowers embodying theinvention covered by my aforesaid prior patent has emphasized the factthat this end play of the cuttershaft, though relatively of limitedrange, is

undesirable inasmuch as it may allow' the end of the shaft to bearagainst the driving wheels of the mower, or it may cause the ends of theteeth of the pinion on said shaft to come into improper contact with anadjacent part of the machine as will be fully explained further on.Furthermore, such endwise movement of the cutter-shaft mightSpecification of Letters Patent.

Patented June 7, 1910.

Serial No. 474,722.

cause the pawl of the ratchet device located in the pinion on said shaftto bind.

The present invention provides a construction and arrangement ofcutter-shaft and bearings therefor whereby substantially all movement ofthe shaft endwise is eliminated, all as fully described hereinafter; andwhen the lawn mower is assembled at the factory the cutter-shaft isadjusted for all time, and in fact no provision is made whereby itsadjustment can be altered, the only adjustment possible being thesetting of the stationary knife toward and from the shaft of the rotarycutter. Another advantage in holding the rotary cutter againstlongitudinal movement is that the edge of the stationary knife neverassumes a wavy edge, as is the case when there is endwise play of thecutter-shaft, and if any depression is worn in the edge of thestationary knife, when the latter is adjusted to the cutter, saiddepression would exactly fit the slight protuberance of the edge of thecutter which caused it:

The invention is illustrated in the accompanying drawings, in which,-

Figure 1 is a side elevation of a lawn mower, a part of the frame beingbroken away. Fig. 2 is a longitudinal section in a plane indicated bythe line 22, Fig. 1. Fig. 8 is a section of one end of a lawn mower inthe same plane as shown in Fig. 2-, but embodying a slight change in therelation of the parts of the bearing as compared with Fig. 2.

In these different figures, a, a represent the two side plates of theframe of a lawn mower secured together by the rod 1) and the bar 6 onwhich the stationary knife 6 is secured, the latter, however, beingshown only in Fig. 1, it being the well known frame construction,whereby the side-plates a are maintained in substantial parallelism.

Each side plate has a projection 0 cast thereon on which thedriving-wheels are supported. These driving-wheels, the traction rim ofwhich is indicated by (Z, have each cast therewith a circular flange,the internal surface of which is a rack e. A long hub (Z on thedriving-wheels fits the projection 0.

The cutter-shaft is indicated by f and is supported in hearings in theside-plates consisting, as generally constructed, of a ballcup g locatedin a recess in the sideplates and having balls therein against which thedone it on the bears. lhe bearings for each end of the shaft areidentical. The ends of the cutter-shaft extend through the bearings andside-plates into the recess shaft (which in this case arethe hubs of thespiders m fixed rigidly on the shaft) is located a stifi spring p,preferablyin the form of a spiral spring washer. The spiders m referredto carry the spiral cutter-blades 0 secured thereto in the usual manner.

When the shaft andits bearings are placed in the assembled frame of themower consisting of theside-plates a, the tie-rod b, and stationaryknife-bar Z2 the springs pare compressed to the proper tension. The

' plnions are then applied to the ends of the cutter shaft and thedriving-wheels mounted on their hubs. I

' When the machine is thus assembled, the springs p exert pressure inopposite directions, one in opposition to the. other. Each spring actsin one direction against the loose cone to hold the tapered bearing endthereof in yielding contact with its seat on the balls in the cups 9,and in the other direction against the hubs of the spiders m, and thusin their action in the last named direction, thesprings oppose eachother, and as they are of as nearly equal resiliency as possible itfollows that when the cones are seated in their bearings any change inthe relation of one side plate relative to the other, or any wear ineither of the bearings will result in a movement of the conessimultaneously to make up for any change of position of the seat of onerelative to the other, for the reason that means are provided at eachend of the shaft to follow up the slightest movement between one of theelements of the bearings and another, and this following up movement iseffected by the constant expansive action of the springs p, each havinga my ,said prior patent, it is obvious that should any wear occur in thebearing of that end of the shaft f which carries the fixed cone, thewhole shaft will be permitted to r teases -1nove-e'ndwise, which wouldresult evenshaped recess formed by the rack e" and the body of thedriving-wheel. On t e other hand, the mounting of the cutter-shaft(which normally has free endwise play) between two springs, as p, whoseexpansive action is applied so as to actin opposite direction on eachend portion of the shaft and endwise thereof, will result in holding theshaft in an approximately fixed position and against any longitudinalmovement, regardless of wear of either or both bear; ings, or of anyracking or working of'the frame parts sup-porting the bearings.

Obviously, the action of the parts would be the same in all respects ifthe springs ;0 were located, as shown in Fig. 3, back of the ball-cups gwhich would be springpressed thereby toward the tapered end of the conesh fixedonthe' shaft to maintain a constant yielding pressure between theparts of the bearing.

What I claim, is V 1. A cutter-shaft for lawn mowers and suitablebearings for the ends thereof, each bearing comprising a member having atapered bearing surface and a member in which said surface is seated,fixed abutments on the cutter-shaft, a spring located between eachbearing and one of said abutments to apply constant endwise pressure toeach end of said shaftin opposed direc tions -to hold said 'members ofthe bearing in operative relation one to the other, and to substantiallymaintain said shaft in a fixed position and against longitudinalmovements.

2. A rotary cutter-shaft for lawn-mowers, and a bearing for each end ofthe shaft, a frame comprising side-plates in which said bearings arelocated, said bearings each comprising two members, one movable towardthe other,fixed abutments on the shaft, and springs under compressionand pressing against said abutments and associated with each bearing tohold said bearing. members in operative relation one to the other, one

of the abutments against which the action of s the springs is exertedbeing on the shaft, whereby the latter is yieldingly maintained alwaysin a fixed position, and against longitudinal movements 7 l 3. Thecombination with the frame of a lawn mower, of a rotary cutter-shaft,bearings for each end thereof comprising a ballcup and balls seated inthe frame, loose cones on the shaft,'fixed abutments on the shaft, and aspring located between the end of each cone and one of said abutments toyieldingly hold the cones to their seats against the said balls, wherebyendwise pressure is exerted 30 against the shaft from each endlongitudinally to position the shaft, substantially as described.

a. An automatic cutter-shaft adjusting device for lawn mowers having incombination with the side frames of the mower, a movable member on eachend of. said shaft, resilient means for independently moving saidmovable members in opposite directions, a bearing element located ineach of said side frames to receive the ends of the shaft, the movablemembers engaging said bearing elements, whereby the resilient memberswill maintain the shaft in substantially a fixed position, as described.

5. The combination with the bearing elements of the opposite ends of thecuttershaft of a lawn mower, adjustable cone members mounted on saidshaft, abutments on said shaft, resilient means for moving said conemembers in opposite directions toward said bearing elements and engagingthe abutments whereby the longitudinal position of the shaft may beconstantly maintained, as described.

6. In a lawn mower, the combination with the side frames thereof, aball-bearing construction for the shaft mounted in each of said sideframes, a movable cone member located on each end of said shaft andengaging the ball-bearing, and resilient means for moving saidcone-members in opposite directions, whereby the shaft is constantlymaintained in a fixed position of adjustment longitudinally considered.

ADELBERT B. CASE.

WVitnesses:

K. I. OLEMoNs, HARRY W. BOWEN.

